§2] 



EFFECT ON METABOLISM AND MOVEMENT 



103 



Fig. 18. — Actinosphseriuin Eichhornii, at the beginning of irritation. The proto- 

 plasm is accumulated along the pseudopodia in drops and spindles. (From 

 Vekwokn, '89.) 



says HoFMEiSTEE ('67, p. 50), "The threads become knotty, 

 tear apart, draw together into short clubs or balls, and fuse 



Fig. 19. — Three pseudopodia of the same individual, much enlarged, a, normal 

 condition ; the axial thread is seen, surrounded by protoplasm. 6, the pseudo- 

 podia at the beginning of stimulation, c, d, the stimulation is continuing, and 

 the axial thread is shortening, e, the three pseudopodia are almost completely 

 retracted. (From Vekworn, '89.) 



partly with the collection of protoplasm lying about the cell- 

 nucleus and partly with the peripheral protoplasmic layer." 



These similar phenomena from various organisms are funda- 

 mental ; how are they to be interpreted ? It is well known 



